Each one of these ducks have a distinctive white poof of feathers on their heads. Not quite an Easter hat, definitely not a pompadour, but more like a cotton ball pillbox.
But last time I was there I saw what appears to be a mallard drake with the same poof on top -- only his was quite grand, traveling from his crown halfway down his shimmery neck. Take a gander:

Really. It's more than a poof, hence the post's title. Anyway, here for your enjoyment is a little of this guy, dabbling among lily pads.
Having spent the better part of an hour scouring duck books and Google to find out what this is all about, I've come up with ZERO. I went to duck ID sites for hunters. I put head plumage in quotes to get as specific as possible. I Googled images using every wording imaginable. The best I found was one picture of one of the caramel colored poofers but it was on a stock photographers site. The caption was as clueless, only offering it is thought they are a hybrid.
Do any of you animal lovers out there have a clue?